On 5/11/06, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote:
Hi Cheng... > --------------------results---------------------------------------- > main posix tid:3086476976 > main pid: 14700 > main tid: 14700 > In the thread 0:posix tid 3086474144 > In the thread 0:pid 14700 > In the thread 0:tid 14701 > In the thread 1:posix tid 3075984288 > In the thread 1:pid 14700 > In the thread 1:tid 14702 I got similar result. "pid"s are same for all threads, tids are unique for each threads, and so is the posix tid. BTW, try this: $ LD_ASSUME_KERNEL=2.4.9 ./testku you will get something like below: main posix tid: 16384 main pid: 4657 main tid: 4657 In the thread 0:posix tid 16386 In the thread 0:pid 4659 In the thread 0:tid 4659 In the thread 1:posix tid 32771 In the thread 1:pid 4660 In the thread 1:tid 4660 Fun isn't it? :) suddenly POSIX tid now use smaller number. Also, since we disable NPTL here, "getpid" returns unique numbers too :) Furthermore, if you trace the code using strace, you will find out that pthread_self doesn't generate any syscall. Thus, my not-so-smart conclusion is, pthread is maintaining its own thread id table, and this id is probably correlated with each current->pid. To be sure, try to dig inside pthread source code.
Hi, I did a quick look at the code of the NPTL. I found that the pthread_self does not return the tid but the address of the struct pthread which is allocated in the stack (at least on i386 and possibly on other Arch too). Struct pthread contains various information used by the pthreaded calls. It created in the stack during pthread creation. pthread_self just finds the structure from stack and return its address. Correct me if i am wrong. Regards Manish Regmi -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
